1. Field of the Invention
The present invention relates to semiconductor processing, and more particularly, to a substrate cleaning apparatus and method.
2. Background of the Related Art
The manufacture of semiconductor components includes many processes and steps. Typical processes include chemical vapor deposition, physical vapor deposition, etching, ion implementation, epitaxial growth, and the like. During one or more of the processes performed in the manufacture of semiconductor devices, the substrate on which the devices are disposed must be cleaned. Cleaning is generally necessary to remove residue which may have accumulated on the devices in previous manufacture steps, which may damage the devices.
One conventional cleaning method involves dipping a substrate, or more commonly a rack of substrates, in an aqueous solution to remove residue from the surface of the substrate. The cleaning solutions are often contained in tanks open to the atmosphere. As a result, airborne particles can enter into the process solutions. Through surface tension, these particles are easily transferred to the substrate surfaces as the substrates are dipped and lifted out of the tanks.
Another example of a conventional technique is known as a cascade rinse. A cascade rinse utilizes a cascade rinser, which includes inner and outer chambers separated by a partition. Rinse water flows from a water source into the inner chamber and then to the outer chamber. A substrate is cleaned by passing the substrate through the rinse water of the inner chamber. This process is often used to neutralize and remove acid from an etched substrate.
One problem with the cascade rinser is that xe2x80x9cdirty waterxe2x80x9d often exists in the inner chamber. The dirty water typically includes residual acid as well as particles that often attach to the substrate. These particles can cause defects in the devices of the substrate, thereby reducing the number of usable dyes on a typical substrate.
Subsequent to a fluid cleaning process, the substrates generally must be dried. Thus, in addition to being ineffective cleaning methods, the foregoing cleaning techniques also suffer from the fact that the substrate must generally be moved to another location to undergo the drying process. Transferring substrates between environments is undesirable, as the potential for contamination increases with each transfer.
As a result of the shortcomings of the processes described above, techniques have been developed to both rinse and dry substrates at one location. One such technique, known as spin-rinse-dry, uses a combination of rinse water to rinse the substrate and high speed rotation to remove the cleaning fluid from the substrate. During the rotation of the substrate, one or more fluids are delivered on the substrate""s surface and allowed to flow outwardly over the substrate as a result of the rotation. The fluids may include chemicals such as a dissolving fluid to react with material in the substrate and water to flush the dissolved material from the substrate""s surface. Drying the substrate is accomplished by continuing to rotate the substrate after terminating the fluid flow. The fluid is removed from the substrate during the dry step as a result of the centrifugal force exerted on the fluid as a result of the rotation and the evaporation of the fluid.
One problem with spin-rinse-dry techniques is the generation of particles during the process cycle. The particles are generated because of the need to chuck the substrate against a support member. Typically, a substrate is positioned on the support member and then chucked thereto by applying a backside pressure. Additionally or alternatively, clamping members disposed at a perimeter portion of the substrate may provide a sufficient force to secure the substrate during the process cycle. In any case, contact between the substrate and mechanical components such as the support member and/or clamping mechanisms, often generate particulates which can contaminate the devices.
As the feature sizes of integrated circuits become smaller, the problems associated with particulates worsen. As a result, current methods and apparatus are not well suited for the next generation of integrated circuits.
Therefore, there is a need for an apparatus and method to clean and dry a substrate.
The invention provides a method and apparatus for cleaning and/or drying a substrate. In a first aspect of the invention, a substrate cleaning chamber is provided comprising a chamber body defining a processing cavity adapted to accommodate a substrate, inlets formed in the chamber body and in fluid communication with the processing cavity, and evacuation ports disposed about the processing cavity at a radial distance from a center axis of the processing cavity.
In another aspect of the invention, the substrate cleaning chamber further comprises a plurality of propulsion channels terminating on upper and lower surfaces of the processing cavity. A fluid delivery system may be coupled to the fluid inlets and to the plurality of propulsion channels.
In yet another aspect of the invention, a processing system comprises a transfer chamber at least one substrate cleaning chamber. In one embodiment the substrate cleaning chamber comprises a chamber body defining a processing cavity adapted to accommodate a substrate and further defining an opening to accommodate transfer of a substrate from the transfer chamber into the processing cavity. At least one fluid inlet is formed in the chamber body and in fluid communication with the processing cavity. One or more gas ejection ports are disposed about the processing cavity at a radial distance from a center axis of the processing cavity and oriented at an angle relative to a radial line originating at the center axis.
In still another aspect of the invention, a method for cleaning a substrate is provided, the method comprising providing a chamber body having a cavity at least partially defined by an upper surface and lower surface, positioning a substrate in the cavity, flowing a first fluid into the cavity and onto the substrate, and flowing a second fluid onto the substrate at an angle to cause rotation of the substrate about a center axis.